1,741 research outputs found
Logistic Map-Based Fragile Watermarking for Pixel Level Tamper Detection and Resistance
An efficient fragile image watermarking technique for pixel level tamper detection and resistance is proposed. It uses five most
significant bits of the pixels to generate watermark bits and embeds them in the three least significant bits. The proposed technique
uses a logistic map and takes advantage of its sensitivity property to a small change in the initial condition. At the same time,
it incorporates the confusion/diffusion and hashing techniques used in many cryptographic systems to resist tampering at pixel
level as well as at block level. This paper also presents two new approaches called nonaggressive and aggressive tamper detection
algorithms. Simulations show that the proposed technique can provide more than 99.39% tamper detection capability with less
than 2.31% false-positive detection and less than 0.61% false-negative detection responses
Enhancing pharmaceutical packaging through a technology ecosystem to facilitate the reuse of medicines and reduce medicinal waste
The idea of reusing dispensed medicines is appealing to the general public provided its benefits are illustrated, its risks minimized, and the logistics resolved. For example, medicine reuse could help reduce medicinal waste, protect the environment and improve public health. However, the associated technologies and legislation facilitating medicine reuse are generally not available. The availability of suitable technologies could arguably help shape stakeholdersā beliefs and in turn, uptake of a future medicine reuse scheme by tackling the risks and facilitating the practicalities. A literature survey is undertaken to lay down the groundwork for implementing technologies on and around pharmaceutical packaging in order to meet stakeholdersā previously expressed misgivings about medicine reuse (āstakeholder requirementsā), and propose a novel ecosystem for, in effect, reusing returned medicines. Methods: A structured literature search examining the application of existing technologies on pharmaceutical packaging to enable medicine reuse was conducted and presented as a narrative review. Results: Reviewed technologies are classified according to different stakeholdersā requirements, and a novel ecosystem from a technology perspective is suggested as a solution to reusing medicines. Conclusion: Active sensing technologies applying to pharmaceutical packaging using printed electronics enlist medicines to be part of the Internet of Things network. Validating the quality and safety of returned medicines through this network seems to be the most effective way for reusing medicines and the correct application of technologies may be the key enabler
The entropy of keys derived from laser speckle
Laser speckle has been proposed in a number of papers as a high-entropy
source of unpredictable bits for use in security applications. Bit strings
derived from speckle can be used for a variety of security purposes such as
identification, authentication, anti-counterfeiting, secure key storage, random
number generation and tamper protection. The choice of laser speckle as a
source of random keys is quite natural, given the chaotic properties of
speckle. However, this same chaotic behaviour also causes reproducibility
problems. Cryptographic protocols require either zero noise or very low noise
in their inputs; hence the issue of error rates is critical to applications of
laser speckle in cryptography. Most of the literature uses an error reduction
method based on Gabor filtering. Though the method is successful, it has not
been thoroughly analysed.
In this paper we present a statistical analysis of Gabor-filtered speckle
patterns. We introduce a model in which perturbations are described as random
phase changes in the source plane. Using this model we compute the second and
fourth order statistics of Gabor coefficients. We determine the mutual
information between perturbed and unperturbed Gabor coefficients and the bit
error rate in the derived bit string. The mutual information provides an
absolute upper bound on the number of secure bits that can be reproducibly
extracted from noisy measurements
KALwEN: a new practical and interoperable key management scheme for body sensor networks
Key management is the pillar of a security architecture. Body sensor networks (BSNs) pose several challengesāsome inherited from wireless sensor networks (WSNs), some unique to themselvesāthat require a new key management scheme to be tailor-made. The challenge is taken on, and the result is KALwEN, a new parameterized key management scheme that combines the best-suited cryptographic techniques in a seamless framework. KALwEN is user-friendly in the sense that it requires no expert knowledge of a user, and instead only requires a user to follow a simple set of instructions when bootstrapping or extending a network. One of KALwEN's key features is that it allows sensor devices from different manufacturers, which expectedly do not have any pre-shared secret, to establish secure communications with each other. KALwEN is decentralized, such that it does not rely on the availability of a local processing unit (LPU). KALwEN supports secure global broadcast, local broadcast, and local (neighbor-to-neighbor) unicast, while preserving past key secrecy and future key secrecy (FKS). The fact that the cryptographic protocols of KALwEN have been formally verified also makes a convincing case. With both formal verification and experimental evaluation, our results should appeal to theorists and practitioners alike
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